Art and apparatus for treating



. Nov. '29, 1933.

5. SMITH ART AND APPARATUS FOR TREATING i'OBAGCO AND THE LIKE Original Filgd' Mar ch 5, 1928 2 Sheets-Sheet 1 canon nloooooan I M. j t ti INVENTOR I ATTORNEY P. 5. SMITH Nov. 29, 193%.

' ART AND APPARATUS FOR TREATING- TOBAGCO AND THE LIKE Original Filed March 5, 1928 2 Sheets-Sheet 2 INVENTOR BY I KTIORNEY Reissued Nov. 29, 1938 -UNITED STATES PATENT OFFICE ART AND APPARATUS FOR- TREATING TOBACCO AND THE Original No. 1,952,781, dated March 27, 1934, Se-

rial No. 259,190, March 5, 1928.

Application for reissue September 12, 1938, Serial No.

32 Claims.

One of the objects of this invention is to pro- V vide a method of conditioning tobacco leaves for use in subsequent stages of manufacture of tobacco products such as cigars, for example, and which may be rapidly and conveniently carried on in practice. Another object is 'to provide a method of the above-mentioned nature capable of producing thoroughly dependable and highly efficient results and readily adaptable to meet the varying conditions met with in the manufacture of tobacco products. Another object is to provide a method of the above-mentioned nature which may be inexpensively carried on and capable of achieving vast savings in time 20 over methods heretofore known and/ or practiced.

Another object is to provide a thoroughly practical apparatus for treatment of tobacco and like products and which will be of compact and durable construction and adapted for rapid and convenient manipulation in carrying out? the process of treatment. Another object is to provide an apparatus of the above-mentioned character capable of rapid and highly efficient action and; well adapted to meet the varying condi- 30 tions of practical use. Another object is to provide an apparatus of the above-mentioned nature capable of simple, dependable and rapid manual control and adapted for rapid charging thereof with the products to be treated and for from the generally somewhat dry and brittle condition of the cured tobacco leaves themselves. If the tobacco leaves are to be used for cigar wrappers, discoloration and spotting thereof have to be carefully avoided. The moistening of tobacco leaves by the water contact method cpnsisting generally in wetting the tobacco by immersion in or by spraying with water and then storing the tobacco to permit equalization of the moisture is highly disadvantageous in that rapid removal therefrom. Another object is to the leaves are usually darkened in color, are oftentimes spotted and unless the method is skilfully carried on become over-wetted so that the leaves are soft, tender and diflicult to work. Another method heretofore carried on is known as the humidor method; this method, however, is inherently very slow, and its space factor is very low. If the leaves are not spaced apart when treated by the humidor method, the time required to approach uniform moistening of the leaves is very greatly increased while the spacing of the leaves results in frequent damage due to the fact that the tobacco leaves are oftentimes dry and brittle. ne of the dominant aims of. this invention is to provide a method and apparatus in which the many disadvantages, some of which have been noted above, of methods and apparatuses heretofore employed are effectively overcome, better results 'achieved, and many thoroughly practical economies effected. Other objects will be in part obvious or in part pointed out hereinafter.

' The invention accordingly consists in the features of construction, combination of elements, arrangements of parts and in the several steps and relation and order of each of the same to one or more of the others, all as will be illustratively described herein, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of the various possible embodiments of the mechanical features 01 this invention.

Figure 1 is a vertical central section through the apparatus.

Figure 2 is a horizontal sectional view on a slightly enlarged scale, as seen along the line 22 of Fig. 1; and

Figure 3 is a vertical central section of a portion of the apparatus taken along the line 3-3 of Fig. 2.

Similar reference characters refer to similar parts throughout the, several views in the drawings.

Refgrring now to the drawings and more particularly to Fig. 1, there is shown at In a supporting frame of any suitable construction adapted to carry what will be termed hereinafter the base portion of the apparatus generally indicated at II; this base portion II is preferably of a generally cylindrical shape and is preferably made of any suitable metal. Spaced inwardly from the outer wall I! thereof is an inner wall I 3 substantially concentric with the outer wall l2, the two walls with the bottom portion therebetween forming a ring-like or annular chamber. The upperportion of the inner wall l3 preferably merges from the substantially circular configuration of the lower portion of the wall mem ber l3 into a substantially square portion with roundedcorners, as is indicated at l4 in Fig. 2, the purpose of which will be more clearly set forth hereinafter. The base portion I I is formed within theinner wall I3 to provide a central receptacle l5 conveniently shaped substantially as shown in Fig. 1, it being noted that the side walls of the receptacle l5 are joined to or preferably integrally formed with the inner wall l3 but taper downwardly and inwardly away from the wall l3 to provide a substantially annular space between the annular chamber l2l3 and the inner receptacle I 5; this annular space is fllled with a suitable heat insulating material indicated at [5. The inner central receptacle l5 preferably extends below the outer portions of. the base portion II and conveniently serves as a means to which the supporting frame HI may be secured to hold the entire apparatus in place. A conduit l1 connects the annular chamber l2 -I3 with the receptacle l5,

Suitably related to the outer wall I! of the base portion II and preferably substantially em-.- bedded therein is an electric heating unit l8 preferably extending around the entire periphery of the base portion Ii. The heating unit is supplied a with energy from any suitable current source,

diagrammatically indicated at l9, and the circuit of the heating unit I8 is completed through a suitable manually controlled switch 20 and through a thermostatically controlled switch generally indicated at 2|, the temperature responsive portionof which extends into the upper portion of the annular chamber l2-l3, as will be clear from Fig. 1.

The annular chamber l2--|3 and the receptacle I! may be supplied with water through a conduit 22 controlled by a valve 23, the conduit 22 leading preferably into the base of the central receptacle I 5. A water gauge generally indicated at 24 serves to indicate the height of the water in the base portion Ii of the apparatus. A drain valve 25 connected in the conduit 22 andbetween the valve 23 and the base portion ll of the apparatus serves to permit the water to be drained out of the apparatus.

In the upper portion of the inner receptacle II are supported a suitable number of spiral coils of conduit or piping and in Fig. 1 I have illustrated two serially connected spiral coils of piping through the coils 26.

A pipe or conduit 3| passes in a generally radial direction through the walls l2 and I3 of the base portion H and extends into the chamber formed by the receptacle l5 to a point substantially centrally thereof and preferably in between the two condensing coils 26. 'Ilo the outer end of the pipe 3! is connected a suitable exhausting apparatus which preferably takes the form and arrangement as shown in Fig. 1. Thus I prefer to employ an exhaust pump diagrammatically indicated at 35, the inlet of which is connected to the the drawings.

pipe 3|, a valve 34 controlling the latter. Ihe outlet of the pump 35 is connected by pipe ill to the, intake of another exhaust pump diagrammatically indicated at 36. Pump 35 is what may be termed a fine pump, while pump 36 is what may be termed a coarse pump, the former being capable of exhausting a vessel to a relatively much lower pressure than the latter. The two pumps I prefer to arrange so that either one or both of them may be operated to exhaust through the pipe 3|. This I may achieve by providing a by-pass pipe 6| about the pump 35, a valve 33 being included in the by-pass pipe SI, and by connecting to the pipe 60 (on the exhaust side of pump 35) a pipe or conduit 62 which may be opened to the atmosphere by a valve 63. A crossconnection 64 conveniently serves to take part in simplifying the connections.

' Thus, it valves 33 and 63 are closed, both the coarse pump and the fine pump are operatively connected to the pipe 3i, and it will be noted that the two pumps are arranged serially. Onthe other hand, if it is desired to make only pump 35 eflective, valve 33 is closed and valve 63 is opened, the pump 35 being thus made to exhaust through the pipe 62. Furthermore, should it be desired'to make effective only the pump 36. then valve 63 is closed and valve 33is opened to connect pump 36 to the pipe 3! by way of the by-pass Bl.

A valve 31 connected to the exterior portion of the pipe 3| permits the latter to be opened to the atmosphere.

The upper portion of the apparatus consists. in part of a preferably domeor bell-like member 38 of preferably substantially circular cross-section and of any suitable heightas will be more clearly set forth hereinafter; the dome-like member 38 is thus shaped to form a counter-part to the base portion ll of the apparatus, and at its lower peripheral portion is suitably formed or shaped to provide spaced peripheral flanges 39 and 40 between and within which is received and held a peripherally extending gasket 4| of any suitable material such as rubber orcork, for example. The upper dome portion 38 rests upon the upper peripheral portion of the wall I2, which is received between the flanges 39 and 40 and is thus made to contact with the gasket 4|. The portion 33 is provided with suitable means such asa lifting ring 42, bymeans of which the upper portion 38 of the apparatus may be lifted off of the lower or base portion II.

The upper substantially square portion l4 ofthe inner wall l3 of the base portion H is adapted to support a series of stacked receptacles 43, 44, 45 etc. These receptacles, hereinafter termed flue-baskets, are adapted to receive the material to be treated and are preferably of substantially similar construction so as to. be interchangeable. A preferred form of construction is illustrated in Each flue-basket preferably consists of a side wall member 46 made preferably of sheet metal, substantially square (see Fig. 2) but with rounded corners. The bottom is preferably in the form of a screen as is indicated at 41 (see Figs. 2 and 3), while the lower end of the sheet metal side wall portion 45 is provided with a flange 48 extending downwardly but displaced inwardly relative to the plane of the side walls 43,

as is clearly shown in Fi 3. Suitable apertures basket and, to facilitate handling of the basket; 75

individually, suitable handles 50 are secured thereto.

Moreover, the upper portion 14 of the wall l3 of the base portion II and the sheet metal side portions 46 of the flue-baskets are of. substantially the same configuration, so'that a flue-basket, such as the basket 43 of Fig. 1, may be set upon the wall portion I4 while upon the flue-basket 43 any suitable number of additional flue-baskets, such as the baskets 44 and 45, for example, may

. be stacked in alignment with each other and with the wall portion I4. In each instance the inner depending flange 48 serves to hold the superimposed parts in alignment and in efiect acts like the male part of a telescoping joint of which the female part is either the wall portion 14 or the side wall 46 of a flue-basket. The height of the apparatus may be suited 'to any desired number of containers or flue-baskets with which it may' be desired to charge the apparatus.

The apparatus is suitably lagged as at 5| with a suitable heat insulating material of appropriate thickness.

Considering now the method of treating to bacco in accordance with my invention, it is first to be noted that tobacco leaves, whether in the form of individual leaves, hands of leaves, or carrots of leaves, may be treated, and the tobacco, in any of these forms, is placed within the flue-baskets. Preferably the tobacco is placed in the baskets somewhat loosely and with the stems or axes of the leaves extending generally parallel to the vertical axis of the flue-basket in which they are placed. In Figs. 2 and 3 is shown a flue-basket 45v filled with hands of leaves indicated at 52, and from Fig. 3 it will be noted that the stem terminal portions of the leaves rest upon the screen bottom 41. Thus the tobacco leaves are stacked not only so that the axes of the leaves extend substantially parallel to the vertical axis of the flue-basket but also so that the weight of the bundles of leaves is transmitted to the bottom screen 41 through the bunched and generally tied together stems, thus preventing'substantial injury to the leaves.

A suitable number of flue-baskets filled with tobacco leaves as above described is then stacked, one upon another, upon the wall portion ll of the base portion ll of the apparatus; the upper dome-like portion 38 is then placed over the stacked flue-baskets and brought to rest upon the upper peripheral portion of the outer wall [2, the weight of the member 38 actinginitially to apply sufllcient' compression to the gasket 4| to make a substantially air-tight joint between the upper and lower portions of the apparatus.

The side walls of the stacked flue-baskets will be seen to form substantially a vertical extension of the upper portion I4 of the inner wall l3 of the base H and form in efifect a fiue connnecting the interior of the inner receptacle 15, by way of the open upper end of the uppermost flue-basket and the lateral passage or flue between the stacked flue-baskets and the dome-like member 38, with the annular chamber |2l3. Furthermore, it will be noted, the entire apparatus is air-tight in that the juncture between the upper portion 38 and the lower portion H of the apparatus is sealed by the gasket 4|.

After having drained off the water through the valve 25 followed by the subsequent closing the latter valve, the heating of the chamber l2--|3 is commenced, as by closure of the switch 20 whichconnects the heating unit I! to the source of current Ill. The thermostatic control switch 2| is adjusted to control the circuit of the heating unit l8 so as to maintain constant a temperature of about 40 C. Valves 29 and 30 are then opened to cause the passage through the condenser coils 26 of cooling water, and valve 31, connected to pipe 3|, is closed. Pumps 35 and 36 are set into operation. Valves 33 and 63 are then closed and valve 34 opened so that both the rough pump and the fine pump proceed to exhaust the apparatus. By way of example, the rough pump 35 may be designed to be capable of reducing the pressure within the apparatus to about 55 mm. of mercury, and the fine pump 35 At this point it may be noted that the steps of my method whereby the air or gaseous content is removed from the apparatus achieve certain very important advantages. The fact may generally be noted that the presence of gases or air greatly retards the diffusion of other gas or vapor molecules and where water vapor is intended to be diffused the presence of gases or air retards the diffusion of the water vapor to a very deleterious extent. Moreover, the rate of moistening of materials like tobacco leaves, for example, is also greatly retarded if the leaves are left in a gaseous atmosphere of substantial pressure; this because the water vapor must by diffusion first penetrate the relatively stationary gas film which contacts with and envelops each leaf. By.appropriatel-y reducing the pressure of the atmosphere within the apparatus the retarding eflect upon the difiusion of water vapor by the presence of air or gas is greatly minimized; more particularly, the collision frequency between watervapor molecules and gas molecules is greatly reduced and thus the diffusion of the water vapor is materially facilitated. .Furthermore, the substantial decrease in the density of the gas in the relatively stationary gas film enveloping each individual,leafiremoves what has heretofore been a serious obstacle to the penetration of water vapor into the tobacco leaf; Thus a highly efiici'ent diffusion of water vapor may be achieved to bring the water vapor into the immediate region of the tobacco leaf, while, due to the great decrease in the density of the gas film, the water vapor may much more readily penetrate the film and be sorbed by the leaf.

The exhaustion of the. apparatus having been effected as above described, I now open valve 23 preferably slowly to permit water to be slowly admitted into the base portion of the apparatus, it being noted that the water intake pipe 22 is connected to the receptacle l5 so that the water enters the latterv first and thereafter supplies chamber l2l3 through the conduit l1. During this relatively slow admission of water to the apparatus, the continued pumping efiects a relatively rapid removal of most, if not all, of the gases dissolved in the water. When suflicient water has been introduced into the apparatus, indicated by the water gauge 24 and approximately to the level illustrative y shown in Fig. 1, the valve 23 is closed. The exhausting may tinue for a few minutes so as to insure the reparatus by way of the water. In this manner a very high percentage, in fact upwards of 99%, of

' the non-condensable gases of the air are removed from the apparatus, its walls, and from the parts therein, as well as from the material to be treated. i

The introduction of the water into the heating chamber l2 l3 under this reduced pressure causes the water promptly to boil at relatively low temperature, the heating unit l8 supplying the heat of evaporation. The heating unit is controlled by the thermostatic switch 2 I as above noted, and, being set for 40 C. by way of illustration, average temperature of water vapor of 40 (3.; this corresponds substantially to a vapor pressure of about mm. of mercury. The water vapor thus produced passes upwardly, as indicated by the arrows 54, between the inner substantially cylindricalwall of the dome-like portion 38 and the stacked substantially square flue-baskets; reaching the top portion of the dome member 38, the water vapor is deflected and thence passes downwardly through one flue-basket after the other, hence sweeps past and into intimate con- ,mainder of the water vapor passes on downwardly in the direction of the arrows 55 into contact with the cooling coils 26, whence con densation takes place and a resultant reduction in pressure immediately beneath the screen bottom of the lowermost flue-basket. The condensed water vapor may accumulate in the receptacle l5 and maintains a supply for the chamber l2-I3 by way of conduit IT.

The condensation that is brought about by way of the condensing coils 26 assists in preventing the establishment of' dynamic equilibrium of the water vaporizing system, it being noted that the sorption by the tobacco of substantial portions of the water vapor is a contributing factor toward this action of the condenser coils. This continued action of preventing establishment of dynamic equilibrium in the evaporation system makes it possible to continue the evaporation of water in the chamber i2-ll at substantially the same temperature (maintained substantially constant by the thermostatic control device 2|) and at substantially the same average pressure, while at the same time an effective movement of water vapor into intimate and emcient contact with the tobacco is achieved. The apertures 49 adjacent the upper ends of the side wall portions 45 of the flue-baskets permit the diversion of water vapor from the upwardly moving steam (indicated by the arrows 54) into the individual flue-baskets which are underneath the uppermost flue-basket; thus, a uniform distribution of water vapor throughout the tobacco in the stacked flue-baskets is eflectively achieved.

Moreover, since the tobacco leaves have been so placed in the flue-baskets that the general planes of the leaves extend vertically, or generally parallel to the downward direction of flow of the water vapor, a high efliciency of exposure of the leaves to the water vapor is achieved; it may additionally be noted, however, that the water vapor in efiect sweeps into contact with and along the tobacco leaves and does so at relatively high velocity, sweeping whatever non-condensable gases that may remain in accumulation on the surfaces of the tobacco leaves out of the way and downwardly into the condensing chamber formed by the receptacle l5. In this chamber these gases are thus made to accumulate, where they maintains substantially constant an may remain, being of greater density than the water vapor itself. I may, however, during the.

only, or I may use only the fine pump 35 but throttled, as by adjusting the .valve 34, so that the reduced total pressure iillustratively, as above, about 2 mm. plus 55 mm.) is not lowered. In thus maintaining the exhausting apparatus in continued operation, I may achieve further distinct advantages. apparatus will remove not only such noncondensable gases that have been swept into the condensing chamber but will also .remove from thelatter a. certain amount of water vapor. Such removal of water vapor from a point generally underneath the stack of flue-baskets acts to assist in preventing the establishment or dynamic equilibrium of the water evaporating system. That is, not only do the condensing coils It, by their action in condensing water vapor, and the sorption of the vapor by the tobacco prevent.

establishment 'of dynamic equilibrium, but also the pump may be utilized to prevent or to assist in preventing establishment of such equilibrium by a physical removal of water vapor itself. Thus a rapid and highly emcient movement of water vapor into contact with the tobacco leaves may be achieved. It is to be understood, however, that highly emcient results may be achieved without continuing the operation of the exhausting apparatus.

The length-of time necessary to appropriately condition tobacco depends upon various factors among which may be noted the quality oi the tobacco, its initial condition as to moisture content, and the manner-in which the tobacco leaves are packed into the flue-baskets. Thus, for ex-. ample, Sumatra tobacco requires a greatertime to condition than Connecticut tobacco. Thus, also, tobacco packed in carrots in the flue-baskets requires a longer time than loosely spaced tobac-' co leaves such as'those of an opened hand; By way'of example merely, it might here be noted that I have been able to achieve uniform and effective conditioning, of the tobacco leaves in less than 5% of the time required by the humidor method hereinabove briefly noted.

When the appropriate period of time has elapsed which, as above noted, is dependent upon various factors but which is exceedingly less than is required by present methods, the heating unit l8-is' cut off from its source as by opening the switch 20. If the pumping apparatus has been maintained in operation, further exhausting is stopped, as by stopping the pump or pumps or by closing valve 34; valve 31 is then opened, but in sucha way as to permit atmospheric air to slowly enter the apparatus. The continued evaporation of water in chamber l2l3 reduces the temperature ofthe water to cut down further evaporation, and preferably also valve 23 is opened to permit the entry of water into the bottom portion of the apparatus in order thus further to lower the temperature of the water in the chamber I2-|3 and thus further to cut down evaporation of the latter. Substantial evaporation, however, soon ceases due to the actions immediately above described, it being also noted that the gradual admission of atmospheric air, the gradual drop in temperature, and

the continued condensation, of water vapor by 75,

For example, the exhausting coils 26 permit the ultimate restoration of the total pressure within the apparatus to substantially atmospheric pressure. The vapor pressure within the apparatus is thus reduced to that at substantially room temperature. In this manner, it is assured that no condensation of water vapor on the tobacco can take place. When the pressure gauge 53 indicates atmospheric pressure, the drain valve may be opened and the water withdrawn from the apparatus. The

dome-like upper portion 38 of the apparatus may then be lifted off by means of the ring 42 at its top and the flue-baskets containing the conditioned tobacco may be removed and may be replaced by other flue-baskets containing tobacco to be treated, whence the operations hereinbefore described may be repeated.

While, as hereinabove noted, I prefer to initially reduce the pressure within the apparatus to one which is-on the order of 2 mm. of mercury, and while in so doing I'prefer to use two such pumps as pumps 35 and 36 hereinabove described, it

I will be understood that many features and advantages of my invention may be successfully achieved in practice by reducing the'pressure within the apparatusto a much lesser extent. For example, I may initially exhaust the apparatus to a pressure on the order of 55 mm; of mercury and in such case I may dispense with the fine pump, like pump 35, or use only the rough pump 36. When, however, I utilize a higher pressure, for example one on. the order of 55 mm. of mercury, the various steps hereinabove described may be practiced but in such case I prefer to maintain the pump in operation throughout the conditioning period so that non-condensable gases may continue to be removed during the conditioning period, because such gases are not as completely removed. For example, if the pressure is reduced to about 2 mm. of mercury in the course of the initial pumping operation, upwards of 99% of the non-conden'sable gases of the air are, as already above noted, exhausted from the tobacco and from the walls and material of the interior of the apparatus. On the other hand, if the apparatus is operated at a pressure of about 55 mm. of mercury, the initial pumping operation removes only about of the non-condensable gases from the apparatus. Hence, at the higher pressures it is desirable and preferred to maintain the pump in operation throughout the conditioning period so as to keep up the removal of the residue of non-condensable gases. Such action, however, as already above noted, has the further advantage that, in

further destroyed and thus more rapid and emcient flow of water vapor into contact with the tobacco may be achieved.

It might also be noted that the decrease in the level of the water in the apparatus as indicated by the water gauge 24 gives a visual indication of the rate of and extent to which the water is dissipated in the form of water -vapor, and where it is feasible or desirable to operate the apparatus during the conditioning period without pumping non-condensable gases and some of the water vapor out of the apparatus the water gauge may thus serve as a substantially accurate guide to the quantity of water which has been taken up by the tobacco. If the pumping operation is continued throughout the conditioning or treating period, appropriate compensation for the withdrawal of water vapor from the apparatus may be made and the water gauge thus utilized to indicate the quantity of water vapor absorbed by the tobacco. Thus it will be seen that the progress of the treatment may be watched and, moreover, that the quantity of water vapor absorbed by the tobacco may by this means also be predetermined.

It is to be understood that I do not limit myself to the reduced pressures which have been hereinabove given by way of example and that many features of my invention may be achieved where the pressures are other than those specifically mentioned above.

It will thus be seen that there has been provided in this invention an art and apparatus in which the several objects hereinbefore noted, as well as many thoroughly practical advantages, are effectively achieved. It will be seen that the method may be rapidly and simply carried on, achieves highly uniform results, makes for great saving in time, and may be carried on with apparatus of simple and thoroughly practical yet inexpensive construction. Moreover, it is to be noted that discoloration and spotting of the tobacco leaves are effectively prevented and that many great advantages over heretofore known methods are achieved. The apparatus will be seen to be of convenient manipulation and capable of accurate control and, moreover, lends itself to rapid and efficient charging thereof with the. products to be treated, as well as removal therefrom. It will also be notedthat the apparatus is of compact construction and has a very high space factor. Furthermore, the art and apparatus thus provided by this invention will be seen to lend themselves readily to the varying conditions of hard prac tical use.

.As many possible embodiments may be made of the mechanical features of the above invention and as the art herein described might be varied in various parts all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim: I

1. The method of treating tobacco and the like, which consists in placing the tobacco in a flue which forms part of an enclosed vessel, exhausting the vessel to a relatively low pressure below atmospheric, evaporating water in the vessel, passing the water vapor to one end of said flue, and maintaining a flow of water vapor through said fine by condensing water vapor at the other end of said flue.

2. The method of treating tobacco and the like, which consists in placing the tobacco in a flue which formspart of an enclosed vessel, exhausting the vessel to a relatively low pressure below atmospheric, evaporating water in the vessel, passing the water vapor to one end of said flue, maintaining substantially constant the temperature of .the water vapor, and maintaining a flow of water vapor through said flue by condensing water vapor at the other end of said flue.

3. The method of treating tobacco and the like, which consists in placing the tobacco in a flue which forms part of an enclosed vessel, exhausting the vessel to a relatively low pressure below atmospheric, evaporating water in the vessel, passing the water vapor to one end of said flue, maintaining substantiallyconstant the temperature of the water vapor, and maintaining a flow of water vapor through said flue by removing water vapor from the other end of said flue.

4. The method of treating tobacco and the like,

which comprises decreasing the density of the gas film adhering to the tobacco, and bringing water vapor into contact with the tobacco under an initial total pressure below 20 millimeters of mercury.

5. The method of treating tobacco and the like, which consists in placing tobacco in a vessel, exhausting the vessel to remove therefrom noncondensable gases and to decrease the density of gas films adhering to the tobacco, evaporating water in the vessel and subjecting the tobacco therein to the water vapor under relatively low total pressure below atmospheric, and preventing increase of said relatively low total pressure.

6. The method of treating tobacco and the like, which consists in subjecting tobacco to water vapor at relatively low total pressure and maintaining substantially constant the temperature of the water vapor.

7. In apparatus of the character described, in combination, a base portion of substantially round cross-section provided with an inner substantially concentric wall adapted to form thereby an inner chamber and an outer annular chamber, a receptacle having a pervious bottom adapted to rest upon said inner wall and by its side wall portions to form an upward extension thereof, a closure member adapted to be mounted upon and sealed to the outer wall of said base member and to form therewith a hermetically sealed vessel closing said receptacle, means for reducing the pressure within said. vessel, means for evaporating water in one of said chambers, and means for condensing water vapor in the other of said chambers.

8. In apparatus of the character described, in combination, a base portion of substantially round cross-section provided with an inner substantially concentric wall adapted to form thereby an inner chamber and an outer annular chamber, a receptacle having a pervious bottom adapted to rest upon said inner wall and by its side wall portions to form an upward extension thereof, a closure member adapted to be mounted upon and sealed to the outer wall of said base member and to form therewith a hermetically sealed vessel enclosing said receptacle, means for evaporating water in one of said chambers, and means for maintaining a movement of water vapor from said one chamber, through said receptacle, andinto the other of said chambers. V

9. In apparatus of the character described, in combination, a base portion of substantially round cross-section provided with an inner substantially concentric wall adapted to form thereby an inner chamber and an outer annular chamber, a receptacle having a pervious bottom adapted to rest upon said inner wall and by its side wall portions to form an upward extension thereof, a closure member adapted to be mounted upon and sealed to the outer wall or said base member and to form therewith a hermetically sealed vessel enclosin said receptacle, means for evaporating water in one of said chambers, means for condensing water vapor in the other of said chambers, and means for removing water vapor from said other of said chambers.

10. In apparatus of the character described, in combination, a vessel provided with means for receiving a product to be treated, means for exhausting the vessel to produce therein a relatively low pressure, and means for maintaining a flow of water vapor past and in contact with the product to be treated at substantially constant temperaatmospheric.

11. In apparatus of the character described, in combination, a base portion of substantially round cross-section provided with an inner sub.- stantially concentric wall adapted to form thereby an inner chamber and an outer annular chamber, a receptacle having a pervious bottom adapted to rest upon said inner wall and-by its side wall portions to form an upward extension thereof, a closure member adapted to be mounted upon and sealed to the outer wall of said base member and to form therewith a hermetically sealed vessel enclosing'said receptacle, means for supplying water vapor to one of said chambers,

and means for reducing the pressure in the other of said chambers.

12. In apparatus or the character described, in combination, a hermetically sealed vessel, means therein forming'substantially a guiding flue and adapted to receive a product to be treated, means for exhausting said vessel to a relatively low pressure, means for supplying water vapor at relatively low total pressure to one end of said flue, and means for condensing water vapor as the latter emerges from the other end of said flue.

13. In apparatus of the character described, in combination, a hermetically sealed vessel, means therein forming substantially a guiding flue and adapted to receive a product to be treated, means within said vessel for receiving a supply of water and connected to one end of said flue,'means for applying heat to evaporate the water in said lastmentioned means, and means for maintaining a difl'erence between the pressure at one end of said flue and the pressure at the other end thereof so that water vappr emerges from the other end of said flue.

14. In apparatus of the character described, in combination, a hermetically sealed vessel, means therein forming substantially a guiding flue and adapted to receive a product to be treated, means within said vessel ror'receiving a supply of water and connected to one end oi! said flue, means for applying heat to evaporate the water in said lastmentioned means, and means for condensin water vapor at the otherend of said flue.

adapted to receive a product to be treated, means within said vessel for receiving a supply of water and connected to one end of said flue, heating means for evaporating water in said lastmentioned means at relatively low temperature, means controlling said heating means so that the temperature or the water vapor is maintained substantially constant, and means for maintaining a flow of water vapor in a direction toward the other end of said flue.

1'7. In apparatus of the character described, in

combination, means for producing water vapor at relatively low substantially constant total pressure, below atmospheric, and means for exposing the product to be treated to said water vapor.

18. In apparatus of the character described, in combination, means for producing water vapor at relatively low total pressure below atmospheric, means for maintaining substantially constant the temperature of the water vapor, and means for exposing the product to be treated to said water vapor.

19. The method of treating tobacco and the like, which consists in placing the tobacco in an enclosed vessel, admitting water into the vessel while maintaining it out of contact, with the tobacco, exhausting gases from the vessel to create in the vessel a relatively low pressure below atmospheric, heating; the water in the vessel to supply water vapor to the tobacco, and maintaining substantially constant the temperature of the water vapor.

20. In apparatus of the character described, in combination, an enclosed vessel adapted to receive tobacco, a pump capable of reducing the pressure in the vessel to a predetermined value, a second pump capable of reducing the pressure in the vessel to a value less than that of which said first pump iscapable, means adapted at will to cause either pump alone or both pumps together to reduce the pressure in the vessel, and means for supplying water vapor to the tobacco in the vessel.

21. In apparatus of the character described,;in

' combination, an enclosed vessel adapted to receive tobacco, a pump capable of reducing the pressure in the vessel to a predetermined value, a second pump capable of reducing the pressure in the vessel to a value less than that of which said first pump is capable, means connecting said pumps serially so that said second-mentioned pump is connected to the exhaust of said firstmentioned pump, and means for supplying'water vapor to the tobacco in the vessel.

'22. In apparatus of the character described, in combination, means for producing water vapor at relatively low total pressure, means forming a path of flow for said water vapor. means for holding a product to be treated in the path of flow or the water vapor, and means for condensing water vapor adjacent the end-of said pathforming means.

23. In apparatus of the character described, in combination, an enclosed vessel, means therein forming a path of flow for water vapor, means for holding tobacco to be treated in the path of flow of the water vapor, means for exhausting the vessel to a relatively low pressure, means for supplying water vapor at relatively low total pressure to said path or flow, said pressures being below atmospheric, and means operable, after the conclusion of the treatment, for slowly admittin air to said vessel and at a rate such that condensation of water vapor upon the tobacco is prevented.

24. In apparatus of the character described, in combination, an enclosed vessel, means therein forming a path of flow for water vapor, means for holding tobacco to be treated in the path of flow oi the water 'vapoa means i'or exhaustin! the vessel to a relatively low pressure, means for supplying water vapor at relatively low total pressure to one end of said path-forming means, and means for condensing water vapor at the exit end 0! said path-forming means.

25. In apparatus of the character described, in combination, an enclosed vessel, means therein forming a path 01 flow for water vapor, means for holding tobacco to be treated in the path of flow of the water vapor, means for exhausting the vessel to a relatively low pressure, means for supplying water vapor at relatively low total pressure to one end of said path-forming means, and means for condensing water vapor at the exit end of said path-forming means, said exhausting means having a connection to a point at the exit end of said path-forming means.

26. In apparatus of the character described, in combination, an enclosed vessel, means therein forming a path of flow for water vapor, means for holding tobacco to be treated in the path of flow oi' the water vapor, means for exhausting the vessel to a relatively low pressure below atmospheric, means in connection with said vessel for holding a supply of water subjected to said pressure, means for heating the water, and means responsive to the temperature of the water for controlling the heating thereof.

27. In apparatus or the character described, in combination, means forming asealed chamber and comprising two inter-fitted sections, one of which is removable with respect to the other, a receptacle for receiving tobacco positioned within said chamber and adapted to be removed therefrom upon removal of one of said sections,

and means tor producing water vapor within said chamber at such a low pressure that the pressure of the atmosphere upon the sections of said chamber holdssaid sections together.

28. The method of treating tobacco and the like, which comprises placing the tobacco in a vessel, exhausting the vessel to a total pressure below 20 millimeters of mercury to remove noncondensable gases therefrom, and then subjecting the tobacco in the vessel to water vapor under relativelylow total pressure below atmospheric.

29. The method of treating tobacco and the like, which comprises placing the tobacco in a vessel, exhausting the vessel, to a total pressure below 20 millimeters .of mercury to remove noncondensable gases therefrom, evaporating water in the vessel and subjecting the tobacco therein to the water vapor under relatively low total pressure below atmospheric.

30. The method of treating tobacco and the like, which comprises placing the tobacco in a vessel, exhausting the vessel to a total pressure below 20 millimeters of mercury to remove noncondensable gases therefrom, subjecting the tobacco to water vapor under relatively low total pressure, and preventing substantial addition of heat to the tobacco under treatment.

31. 'Ihe method oftreating tobacco and the like, which comprises placing the tobacco in a vessel, exhausting the vessel to a total pressure 

